From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755872AbcB0AKr (ORCPT ); Fri, 26 Feb 2016 19:10:47 -0500 Received: from smtp.codeaurora.org ([198.145.29.96]:44413 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755779AbcB0AKp (ORCPT ); Fri, 26 Feb 2016 19:10:45 -0500 Date: Fri, 26 Feb 2016 16:10:42 -0800 From: Stephen Boyd To: Shawn Lin Cc: Michael Turquette , linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] clk: check the actual phase if get_phase is provided Message-ID: <20160227001042.GC28849@codeaurora.org> References: <1455759499-9622-1-git-send-email-shawn.lin@rock-chips.com> <20160225231458.GH28849@codeaurora.org> <56CFA8B4.7070600@rock-chips.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <56CFA8B4.7070600@rock-chips.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/26, Shawn Lin wrote: > On 2016/2/26 7:14, Stephen Boyd wrote: > >On 02/18, Shawn Lin wrote: > >>set_phase does sanity checking of degree and ask sub-driver > > [...] > > >>already there. > >> > >>Signed-off-by: Shawn Lin > >> > >>--- > > > >Knee jerk reaction is why does the provider code set a phase that > >isn't requested? Do we need some sort of clk_round_phase() API > >that parallels clk_round_rate() so that drivers know what phase > >they're going to get? Or do drivers not care what phase they get > >when they call clk_set_phase()? > > Hi Stephen, > > drivers should care what phase they get when calling clk_set_phase(i.e > the drivers setting phase to do tuning work should know what the actual > degrees is, which is important for them to decide the sample window > algorithm). > > By looking into the two drivers who use set_phase/get_phase pair > currently, they actually both don'e care what the actual degrees when > they call clk_set_phase. I think that is because the drivers are used > for specific platform which support 0~360 implicitly. But the situation > is NOT always right for cross-platform drivers. So add some sort of > round_phase API is probably sane ? > Do you have such a platform or driver though? I'd rather not do anything unless we actually need to. -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project